Alternatives for "free software" were sought for marketing purposes and because of a perceived "moralising and confrontational" attitude that had been associated with the term.[by whom?][2] In addition, the "available at no cost" ambiguity of the word "free" was seen as discouraging business adoption.[3] In a 1998 strategy session in California, "open source software" was selected by Todd Anderson, Larry Augustin, Jon Hall, Sam Ockman, Christine Peterson, and Eric S. Raymond.[4] Richard Stallman had not been invited.[5] The session was arranged in reaction to Netscape's January 1998 announcement of a source code release for Navigator (as Mozilla). Those at the meeting described "open source" as a "replacement label" for free software,[6] and the Open Source Initiative was soon-after founded by Eric Raymond and Bruce Perens to promote the term as part of "a marketing program for free software".[7] Stallman and others object to the term "open source software" because it does not make people think of the freedom that the software in question gives users, or guarantee it (a minority of open source software is released under a non-liberal license).

Each of the terms "free software" and "open-source software" has fans and critics. Partly because of the failure to adopt one specific term, other terms have been proposed. These include "software libre" (or libre software), "FLOSS" (free/libre and open-source software), and "FOSS" (or F/OSS, free and open-source software). These terms share almost identical licence criteria and development practices.

"Software Libre" was first used publicly in 2000, by the European Commission.[10] The word "libre", borrowed from the Spanish and French languages, means having liberty. This avoids the freedom/cost ambiguity of the English word "free".

"FLOSS" was used in 2001 as a project acronym by Rishab Aiyer Ghosh for free/libre and open-source software. Later that year, the European Commission (EC) used the phrase when they funded a study on the topic.[11]

Unlike "libre software", which aimed to solve the ambiguity problem, "FLOSS" aimed to avoid taking sides in the debate over whether it was better to say "free software" or to say "open-source software".

Proponents of the term point out that parts of the FLOSS acronym can be translated into other languages, with for example the "F" representing free (English) or frei (German), and the "L" representing libre (Spanish or French), livre (Portuguese), or libero (Italian), and so on. However, this term is not often used in official, non-English, documents, since the words in these languages for "free as in freedom" do not have the ambiguity problem of English's "free".

By the end of 2004, the FLOSS acronym had been used in official English documents issued by South Africa,[12] Spain,[13] and Brazil.[14]

Richard Stallman endorses the term FLOSS to refer to "open source" and "free software" without necessarily choosing between the two camps, however, he asks people to consider supporting the "free/libre software" camp.[15][16] Stallman has suggested that the term "unfettered software" would be an appropriate, non-ambiguous replacement, but that he would not push for it because there was too much momentum and too much effort behind the term "free software".

While the term "free software" is associated with FSF's definition, and the term "open source software" is associated with OSI's definition, the other terms have not been claimed by any group in particular. FSF's and OSI's definitions are worded quite differently but, the latter was based on FSF's definition and the set of software that they cover is almost identical.[18][19]

All of the terms are used interchangeably, the choice of which to use is mostly political (wanting to support a certain group) or practical (thinking that one term is the clearest).

Apart from these two organisations, the Debian project is seen by some to provide useful advice on whether particular licences comply with their Debian Free Software Guidelines. Debian does not publish a list of "approved" licences, but its judgments can be tracked by checking what licences are used by software they have allowed into their distribution.[21] In addition, the Fedora Project does provide a list of approved licences (for Fedora) based on approval of the Free Software Foundation (FSF), the Open Source Initiative (OSI), and consultation with Red Hat Legal.[22]

Richard Stallman's Free Software Definition, adopted by the Free Software Foundation (FSF), defines free software as a matter of liberty, not price.[23] The earliest known publication of the definition of his free software idea was in the February 1986 edition[1] of the FSF's now-discontinued GNU's Bulletin publication. The canonical source for the document is in the philosophy section of the GNU Project website. As of April 2008, it is published there in 39 languages.[24]

Unlike libre software, which aimed to solve the ambiguity problem, FLOSS aimed to avoid taking sides in the debate over whether it was better to say "free software" or to say "open-source software".

Proponents of the term point out that parts of the FLOSS acronym can be translated into other languages, with for example the F representing free (English) or frei (German), and the L representing libre (Spanish or French), livre (Portuguese), or libero (Italian), liber (Romanian) and so on. However, this term is not often used in official, non-English, documents, since the words in these languages for free as in freedom do not have the ambiguity problem of free in English.

By the end of 2004, the FLOSS acronym had been used in official English documents issued by South Africa,[12] Spain,[30] and Brazil.[14]

The terms "FLOSS" and "FOSS" have come under some criticism for being counterproductive and sounding silly. For instance, Eric Raymond, co-founder of the Open Source Initiative, has stated:

"Near as I can figure ... people think they’d be making an ideological commitment ... if they pick 'open source' or 'free software'. Well, speaking as the guy who promulgated 'open source' to abolish the colossal marketing blunders that were associated with the term 'free software', I think 'free software' is less bad than 'FLOSS'. Somebody, please, shoot this pitiful acronym through the head and put it out of our misery."[31]

Raymond quotes programmer Rick Moen as stating:

"I continue to find it difficult to take seriously anyone who adopts an excruciatingly bad, haplessly obscure acronym associated with dental hygiene aids" and "neither term can be understood without first understanding both free software and open source, as prerequisite study."

The primary difference between free software and open source is one of philosophy. According to the Free Software Foundation, "Nearly all open source software is free software. The two terms describe almost the same category of software, but they stand for views based on fundamentally different values."[32]

There is also a class of software that is covered by the names discussed in this article, but which doesn't have a licence: software for which the source code is in the public domain. The use of such source code, and therefore the executable version, is not restricted by copyright and therefore does not need a free software licence to make it free software. However, not all countries have this form of "public domain" regime.

Further, for distributors to be sure that software is released into the public domain, the usually need to see something written to confirm this. Thus even without a licence, a written note about lack of copyright restrictions often still exists and this could be compared to a form of licence.

The free software community in some parts of India sometimes uses the term "Swatantra software" since the term "Swatantra" means free in Sanskrit, which is the ancestor of all Indo-European Languages of India, including Hindi, despite English being the lingua franca.[34] Other terms such as "kattatra menporul(கட்டற்ற_மென்பொருள்)" for free software, where kattatra means free and menporul means software is also being used in Tamil Nadu and Tamils in other parts of the world. In The Philippines, "malayang software" is sometimes used. The word "libre" exists in the Filipino language, and it came from the Spanish language, but has acquired the same cost/freedom ambiguity of the English word "free".[35] According to Meranau "Free" is KANDURI, Diccubayadan, Libre.

^"History of OSI". conferees decided it was time to dump the moralizing and confrontational attitude that had been associated with "free software" in the past and sell the idea strictly on the same pragmatic, business-case grounds

^"Frequently Asked Questions". Open Source Initiative. Archived from the original on April 23, 2006. How is "open source" related to "free software"? The Open Source Initiative is a marketing program for free software.